Composition to be used in the resin injection molding technique, containing low molecular weight compounds jointly forming a hybrid network

Abstract

The present invention relates to a reaction injection molding process, to a composition utilized therein as well as to a kit of parts from which the composition can be obtained. In particular, the process includes the use of a composition which contains at least 70% of low molecular weight compounds which are capable of forming a crosslinked polymer. The first component of the composition is a compound with at least an ethylenic unsaturation and an isocyanate-reactive group. The second component of the composition contains an ethylenically unsaturated monomer capable of copolymerizing with the first component. The third component of the composition is a polyisocyanate. Polymerization of the first and second components takes places prior to the reaction between the first and third components.

I claim: 
     
       1. A reaction injection molding process for making products from a composition which contains at least 70% of low molecular weight compounds capable of forming a crosslinked polymer, which composition contains a first component consisting of a compound with at least an ethylenic unsaturation and an isocyanate-reactive group, a second component containing an ethylenically unsaturated monomer capable of copolymerizing with the first component, and, as a third component, a polyisocyanate, wherein the first, second and third components are monomers having a molecular weight less than 1000, the first component consists of a monomer having 1 terminal vinyl group and 1 isocyanate-reactive group per molecule and a molecular weight less than 500, wherein the polymerization of the first and second components takes place before the reaction of the first and third components. 
     
     
       2. Process according to claim 1, characterized in that the composition also contains 2 to 20% of a fourth component, which component has two or more isocyanate-reactive groups or two or more ethylenic unsaturations and a molecular weight of between 500 and 3000. 
     
     
       3. Process according to claim 1, characterized in that the composition consists of monomers with a molecular weight lower than 500, the first component of which consists of monomers with a molecular weight lower than 400. 
     
     
       4. Process according to claim 1, characterized in that the isocyanate-reactive group is a hydroxyl group. 
     
     
       5. Process according to claim 1, characterized in that the first component has the following general formula: ##STR2## where R is a hydrogen or methyl, R 1  is an alkylene group with 2 or 3 carbon atoms and n is a whole number between 1 and 6. 
     
     
       6. Process according to claim 1, characterized in that the ratio of the second component and the first component is between 95:5 and 5:95 (in weight). 
     
     
       7. Process according to claim 1, characterized in that the third component contains at least an average of 1.7 isocyanate groups. 
     
     
       8. Process according to claim 1, characterized in that the third component contains an average of 2.2 to 2.7 isocyanate groups. 
     
     
       9. Process according to claim 1, characterized in that the second component is chosen from the group consisting of styrene, p-methylstyrene, vinyl toluene, methyl-, ethyl-, propyl acrylate or methacrylate. 
     
     
       10. Process according to claim 1, characterized in that the composition has a viscosity of between 1 and 150 mPa.s measured at 23° C. 
     
     
       11. Process according to claim 1 wherein the first component consists of at least 70% of the hydroxylester of (meth)acrylic acid. 
     
     
       12. Product obtainable by the process according to claim 1. 
     
     
       13. Composition to be used in Resin Injection Molding technique (RIM) which contains at least 70% of low molecular weight compounds capable of forming a crosslinked polymer, which composition contains at least a first component which consist of a compound with at least an ethylenic unsaturation and an isocyanatereactive group and which has 1 terminal vinyl group and 1 isocyanate-reactive group per molecule, a second component containing an ethylenically unsaturated monomer capable of copolymerizing with the first component, a third component which is a polyisocyanate, and 2-20% of a fourth component containing at least an isocyanate reactive group or an ethylenic unsaturation, wherein the first, second and third components are monomers having a molecular weight less than 1000, the first component having a molecular weight lower than 500, the fourth component of which has two or more isocyanate-reactive groups or two or more ethylenic unsaturations and a molecular weight between 500 and 3000, wherein the polymerization of the first and second components takes place before the reaction of the first and third components. 
     
     
       14. Kit of parts consisting essentially of a first element and a second element, said first element containing a compound with at least an ethylenic unsaturation and an isocyanate-reactive group, and said second element containing a polyisocyanate, wherein at least about 70% of said first component is the hydroxyl ester of (meth)acrylic acid. 
     
     
       15. Kit of parts according to claim 14, which consists essentially of said first element and said second element, wherein said compound contained in said first element comprises a first component and is represented by the following general formula: ##STR3## where R is a hydrogen or methyl, R 1  is an alkylene group with 2 or 3 carbon atoms and n is a whole number between 1 and 6, and with a molecular weight lower than 500;   wherein said polyisocyanate of said second element comprises a third component and has a molecular weight less than 1000;   wherein said first element or said second element contains a radical catalyst;   wherein at least said first element or said second element contains a second component which is a monomer having one ethylenic unsaturation and having a molecular weight below 1000; and   wherein the weight ratio of the second component to the first component is between 95:5 and 5.95.